PROCELLAKIID^. 



409 



Schizognathous and holorhinal. The rhamphotheca, i.e. horny 

 covering of the bill, is more or less distinctly separated into several 

 pieces by narrow grooves. Bill curved down at tip and generally 

 sharply hooked. 3 front toes completely connected by webs, 

 hallux small, rudimentary, or absent. Wings long, 10 developed 

 primaries, first (11th) rudimentary. 15 cervical vertebrae. Young 

 nidicolous. Some species dichromatic ; some crepuscular and 

 nocturnal in habits. One egg only. Peculiar musky smell, different 

 in various genera. Division into families not satisfactory, therefore 

 here omitted. Over 130 species in all seas. 



Family PROCELLARIID.E. 

 See characters, etc., under Order Tubinares. 



Key to genera of Family Procellariid^. 



< Nostrils lateral, separated by wide culrren, wings longer 



f Nostrils on top of culmen, wings shorter than 40 cm., 

 a hind toe present 9 



I N 



than 40 cm., no hind toe 



1st developed primary shorter than 2nd . 3 



1st developed primary equal to 2nd or longer . 6 



Tarsus covered in front with an undivided shield, wings 



under 130 mm. . 



Tarsus with small scutes, wings over 130 mm. . 4 



Underside white ....... 



Underside brown ...... 5 



Tarsus under 30 mm., webs between toes uniform black 

 Tarsus over 30 mm., webs between toes partially yellow . 



Rectrices 14 ....... • 



Rectrices 12 . . . . • • 7 



Tarsus laterally compressed, front of tarsus with a more 

 or less sharp ridge, median depressed part of culmen 

 about half length of bill ...... 



Tarsus not distinctly compressed, front without a sharp 

 ridge, median depressed part of culmen less than half 

 length of bill .... ... 8 



2 { 



f 



Wing under 210 mm. 

 Wing over 210 mm. 



Diomedea 



Hydrobates 



Pelagodroma 



Oceanodro?na 

 Oceanites 



Fulmarus 

 Pufflnus 



Bulweria 

 Pterodro?na 



Genus HYDROBATES. 



Hydrobates, Boie, Isis, 1822, p. 562 (Type by subsequent designation — 

 Salvin, Cat. B. Brit. Mus., xxv, 1896 — H. pelagica). 



Small Petrels, smaller in wing than Swifts, dark sooty-brown, 

 with white rump. Nostrils in one tube on top of culmen. Plumage 

 very thick and soft. Wings long and pointed, second developed 

 primary longest. Tail slightly rounded, 12 rectrices. Tarsus very 

 little longer than middle toe with claw and about half as long as 

 femur, front divided into scutes. 2 species, 1 Palsearctic. 



